There are several methods of disabling UAC on vista
YOu can try this
1.Click Start and then open Control Panel.
2.In the Control Panel, click User Accounts and Family Safety.
3.Click User Accounts.
4.Click Turn User Account Control on or off.
5.Clear the check mark on the box beside the Use User Account Control (UAC) to help protect your computer option.
6.Click OK.
You should restart the computer when prompted
this change will affect for all users on the computer.
For BHO
Open Internet Explorer
Click the Tools button, and then click Manage Add-ons.
you will see the BHO here under Toolbars and Extensions add-on types.
Enable this if it is disabled.
hope this helps.
YOu can try this
1.Click Start and then open Control Panel.
2.In the Control Panel, click User Accounts and Family Safety.
3.Click User Accounts.
4.Click Turn User Account Control on or off.
5.Clear the check mark on the box beside the Use User Account Control (UAC) to help protect your computer option.
6.Click OK.
You should restart the computer when prompted
this change will affect for all users on the computer.
For BHO
Open Internet Explorer
Click the Tools button, and then click Manage Add-ons.
you will see the BHO here under Toolbars and Extensions add-on types.
Enable this if it is disabled.
hope this helps.